Fluid distribution system operated by pressure signal

ABSTRACT

A sprinkler system has a plurality of sprinklers connected to a main water supply. A control system includes main flow control valve units for controlling water flow to said sprinklers, said valve units being controlled by pressure signals of predetermined values from a pressure signal control means. Each valve unit includes a manually actuated valve and a pressure actuated valve.

United States Patent [191 Kah, Jr.

[ Mar. 19, 1974 FLUID DISTRIBUTION SYSTEM OPERATED BY PRESSURE SIGNAL [76] Inventor: Carl L. C. Kah, Jr., 778 Lakeside Dr., North Palm Beach, Fla. 33408 [22] Filed: Jan. 24, 1972 [21] Appl. No.: 220,358

[52] US. Cl 239/11, 239/66, 137/119 [51] Int. Cl B0511 17/04 [58] Field of Search 239/11, 71, 76, 66; 169/8,

[56] References Cited UNITED STATES PATENTS 9/1912 Zint 239/66 4/1954 Richardsn 3,519,016 7/1970 Kah Jr. et a1. 239/66 3,578,245 5/1971 Brock 239/66 3,635,237 l/1972 Kah, Jr. 239/66 3,386,460 6/1968 Dean 239/69 3,400,891 9/1968 Mattwell 239/69 Primary Examiner-Lloyd L. King Attorney, Agent, or Firm-Jack McCarthy [5 7] ABSTRACT A sprinkler system has a plurality of sprinklers connected to a main water supply. A control system includes main flow control valve units for controlling water flow to said sprinklers, said valve units being controlled by pressure signals of predetermined values from a pressure signal control means. Each valve unit includes a manually actuated valve and a pressure actuated valve.

19 Claims, 9 Drawing Figures SECTION 3 SECTION 3 SECTION 2\, j 5

PAIENIEnuan 19 m4 smnnra -5m 295mm 5 295mm PATENTEDHAR 1 919?;

FIG.

SHEET 2 [IF 4 FLUID DISTRIBUTION SYSTEM OPERATED BY PRESSURE SIGNAL BACKGROUND OF THE INVENTION The invention relates generally to fluid distribution or sprinkler systems and valves included therein for irrigation purposes. Previously, pressure sequencing valves required a pressure pulsing of a fluid in the main line. See Application Ser. No. 90,732 for IRRIGA- TION SPRINKLER SYSTEM CONTROL EMPLOY ING PILOT OPERATED, PRESSURE ACTUATED AND SEQUENCED VALVE ASSEMBLIES of Carl L. C. Kah, Jr., filed Nov. 18, 1970 now continuing Application Ser. No. 222,600, filed Feb. 1, 1972, now U.S. Pat. No. 3,747,620.

SUMMARY OF THE INVENTION It is a primary object of the invention to provide a sprinkler system for irrigating with control of sprinklers or sprinkling sections by flow control valves which can be selectively signaled open or closed by a tube pressure signal separate from the main flow system.

Another object of the invention is to provide a pressure signal control means which will direct proper signal levels to the sprinkler system to irrigate the desired sections.

In accordance with the invention, a main flow control valve unit is provided which is responsive to a desired pressure signal. the main flow control valve unit including a pressure actuated valve which can be changed to be responsive to different desired pressure signals.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a portion of a sprinkler system showing a main water conduit and supply, and a pressure signal tube with pressure signal control means.

FIG. 2 is a schematic view of the pressure signal control means showing a pressure signal source and a pressure signal controller.

FIG. 3 is a sectional view of the main flow control valve unit.

FIG. 4 shows the closed position of the valve surfaces of the pressure actuated valve at a low pressure signal.

FIG. 5 shows the open position of the valve surfaces of the pressure actuated valve at an actuating pressure signal.

FIG. 6 shows the closed position of the valve surfaces of the pressure actuated valve at a high pressure signal.

FIG. 7 is a view showing the valve surfaces formed by a plurality of parts.

FIG. 8 is a modification of the main flow control valve unit.

' FIG. 9 is another modification of the main flow control valve unit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a portion of a sprinkler system is shown with a main water supply 2 and 2A connected to a plurality of sprinkler units 4 by main water conduits 6 and branch conduits 8. A main flow control valve unit 50 is located in each branch conduit 8 between the main conduit 6 and the sprinkler unit 4 or sprinkler units 4 connected to each branch. The sprinkler unit 4 or sprinkler units 4 of each branch conduit 8 are referred to as a watering section of the total area being irrigated. A section" can be serviced by one or more branch conduits 8. The main flow control valve units 50 are selectively controlled; that is, signaled open" or closed, to direct water to a specific section" by selected pressure signals. When more than one branch conduit 8 is used for a section," the cooperating main flow control valve units 50 are all adjusted to open for the same selected pressure signal. The selected pressure signals are delivered to the main flow control valve units 50 by a pressure signal tube 14 from a pressure signal control means 10.

While many different sections" can be used in a sprinkler system, in the system described. eight sections" are used; therefore, eight different selected pressure signals are needed for opening the units 50. For the system described, the eight open pressure signals selected are 10 psi, 20 psi, 30 psi, 40 psi, 50 psi, 60 psi, psi and psi. It is to be understood that a main flow control valve unit 50 can be open for a small range of pressures, for example, the unit 50 which has 50 psi for its selected pressure signal for opening it, may be open for a few psi on either side of 50 psi; for example, 47 psi to 53 psi. It is only necessary that each unit 50 having a selected open pressure signal for opening, will be closed when each other unit having other selected *open" pressure signals is open. While a 10 psi separation is used between signal pressure levels, other values can be used if desired, such as 20 psi. The greater value would insure better control isolation of unit selection.

The pressure signal control means 10 shown, FIG. 2, has a passageway 16 therein having an inlet end and an outlet end. The inlet end is connected to an inlet line 18 from pressure source 12 and the outlet end is connected to a pressure signal tube 14. In the device disclosed having eight open" pressure signals from 10 psi to 80 psi, the pressure source must be at least 80 psi. A pressurizing solenoid valve 20 is located in the passageway 16. A pressure sensing transducer 22 is connected to the passageway 16 by a short passageway 24 and a pressure reducing solenoid valve 26 is connected to the passageway 16 by a short passageway 28. A dump line 30 is also connected to the valve 26.

An electrical signal tube pressure controller 32 receives an electrical output signal on line 23 from the pressure sensing transducer 22 which is representative of the pressure in the signal tube 14, and an electrical signal on line 35 from an electrical signal producing device 34 which is representative of the pressure desired in signal tube 14. The electrical signal producing device 34 can be a simple power supply and a voltage dividing resistance network. Section" selection button switches are provided for selecting the desired output voltage signal which represents a desired open" pressure signal or level in the signal tube 14. The eight output electrical signals in the device shown, for the eight selection buttons numbered 1 to 8, are representative of pressures equal to 10 psi, 20 psi, 30 psi, 40 psi, 50 psi. 60 psi, 70 psi and 80 psi. pressures usable in the signal tube 14 for placing different valve units 50 in an open" position.

The electrical signal tube pressure controller 32 compares the selected output signal on line 35 from the electrical signal producing device 34 with the signal on line 23 from the pressure sensing transducer 22 which is representative of the actual pressure in signal tube 14. If the two signals are the same, then the pressure selected by the "section" selective buttons is present in the tube 14. If the signal on line 23 is greater than the signal on line 35, the pressure controller 32 will signal valve 26 to open from its normally closed position by connection 27, connecting passageway 28 to dump line 30; this will reduce the pressure in passageway 16 and therefore in signal tube 14. When the pressure in signal tube 14 reaches the desired pressure, wherein the signal on line 23 will then be equal to that on line 35, the valve 26 will be repositioned to its closed position.

If the signal on line 23 is less than the signal on line 35, the pressure controller 32 will signal valve 20 to open from its normally closed position by connection 21, opening passageway 16. Since the pressure source 12 contains a pressure greater than the highest necessary for the control of all of the main flow control valve units 50, the pressure in passageway 16 attempts to rise. This will increase the pressure in passageway 16 and therefore in signal tube 14. When the pressure in signal tube 14 reaches the desired pressure wherein the signal on line 23 will then be equal to that on line 35, the valve 20 will be repositioned to its closed position.

The electrical signal tube pressure controller 32 shown in FIG. 2 may be connected to an automatic electronic signal producing device which will provide desired electrical signals in any desired sequence and for any desired time length. This would be useful for night watering of a golf course, for example.

A simpler control of pressure in signal tube 14 which would provide the open" pressure signals to operate the system. could be, for example. eight different pressure sources of psi to 80 psi and a selector valve for directing one of the pressures to the signal tube 14. Manual positioning of the selector valve would open the desired valve units 50. The selector valve could be automatically positioned, if desired. A standard feedbleed type mechanical pressure regulator could also be adjusted as desired to provide the desired signal tube actuating pressure level signals.

Each main flow control valve unit 50 (see FIG. 3) is comprised of three main parts;

1. a main flow valve 52,

2. a pressure actuated valve 54, and

3. a manually actuated valve 56.

Main flow valve 52 is formed having a housing 58 of two parts. a body 60 and a cover 62, with a valve diaphragm 63 therebetween. Housing body 60 is comprised having on one side thereof an annular surface 66 with a dish-like surface 68 extending inwardly in a direction away from the surface 66. The dish-like surface 68 extends inwardly to a short cylindrical section 70 which projects into said dish-like surface and terminates at an annular valve seat 72. An inlet 74 and an outlet 76 are formed integral with part 60 at diammetrically opposed positions. A passageway 78 is formed in part 60 connecting the inlet 74 to the end of the cylindrical section 70 under said dish-like surface. A passageway 79 is formed in part 60 interconnecting the outlet 76 to an opening 81 in the surface 68. Inlet 74 has internal threads 75 and outlet 76 has internal threads 77.

Housing cover 62 is formed having an annular surface 80 thereon for cooperating with the annular surface 66 of the housing body 60. A dish-like surface 82 extends away from the annular surface 80 in a direction away from the body 60. The dish-like surface terminates in a flat circular surface at the closed end thereof.

The valve diaphragm 63 is positioned with its edge between the annular surface 66 of body 60 and the annular surface of the cover 62. The center of the valve diaphragm 63 is formed having a circular section 84 which is sized to cover the annular valve seat 72. A recess 86 is formed in the circular section of the valve diaphragm facing the cover member 62. Aligned therewith is a recess 88 in the flat circular surface of the inner side of the cover 62. A spring 89 is positioned therebetween to lightly bias the valve diaphragm towards a closed position against the valve seat 72.

In an assembled main flow valve 52, a passageway is formed between the inlet 74 adjacent the internal threads 75 to the inner dish-like surface 82 of the cover 62. This passageway is formed by aligned passage 90, hole 92 and passage 94 and intersecting passage 96. Passage 90 is in body 60, hole 92 is in diaphragm 63 and passages 94 and 96 are in cover 62. A restriction 98 is formed in the passage 94 between the inlet 74 and passage 96. Passage 94 extends into the center of the bottom of a threaded recess 99 in an outer surface of cover 62 for a purpose to be hereinafter described.

Diammetrically opposed from said recess 99, on the outer surface of cover 62, a threaded recess 59 is formed having a countersunk cylindrical bottom section 61 with an annular shoulder 65 formed at their intersection. A passage 67 connects the interior of dishlike surface 82 to the cylindrical section 61.

The manually actuated valve 56 is formed having a threaded portion to engage the threaded recess 99. A passageway 101 extends from the lower end of the threaded portion and exits at 103. A movable threaded valve member has a lever means for turning it to open or close passageway 10] for manually operating the main flow valve 52.

The pressure actuated valve 54 is formed having a housing 100 of two main parts, a lower body portion 102 and an upper body portion 104 with a valve actuator diaphragm 126 therebetween. Lower housing body 102 is formed of a short cylindrical section with a flange 106 at one end and being externally threaded at 108 on the other end for engagement with threaded recess 59. A short conduit section 110 for venting fluid flow to an ambient pressure to provide an ambient pressure reference for the lower side of the diaphragm, extends radially from said short cylindrical section between said flange 106 and threaded part 108. Upper body portion 104 is formed of a short cylindrical section with a flange 116 at one end and being externally threaded at 118 on the other end. This end of the cylindrical section is also internally threaded at 120. A short conduit section 122 extends radially from said short cylindrical section between flange 116 and threaded part 118 and is connected to the signal pressure tube 14 for a purpose to be hereinafter described.

In an assembled pressure actuated valve 54, flange 106 is positioned adjacent flange 116 with the outer edge of diaphragm 126 being held therebetween. While flanges 106 and 116 can be held together by any means desired, a circular clamp is shown positioned over the ends of the flanges. A bead is formed on one side of the circular outer edge of the diaphragm which fits in a small recess on the face of flange 106. The mating surface of each flange is formed having an angular countersunk face to permit movement of the center part of said diaphragm in an axial direction for a predetermined distance with respect to said short cylindrical section in a manner to be hereinafter described.

A cylindrical cup-like member 130 is positioned within the short cylindrical section of upper body portion 104 with its bottom against diaphragm 126 while an adjusting screw 132 is located threadably engaging the internally threaded section 120 of the upper body portion 104. In order to limit upward movement of said cup-like member 130, an outer cylindrical flange 133 extends outwardly from the bottom thereof for engagement with a recess 131 in the flange 116. A spring 134 is positioned between the inside of cup-like member 130 and the bottom of adjusting screw 132. A protective cap 119 has internal threads which engage the external threads 118 of the upper body portion 104. An O-ring seal is provided to prevent leakage therefrom.

A valve member 140 is positioned in the short cylindrical section of the lower housing body 102 and is formed having a cup-like member 142 with its bottom against diaphragm 126 and with a valve stem 144 extending therefrom away from the diaphragm. The free end of valve stem 144 is formed having two valve surfaces 146 and 148 thereon spaced by a connecting pin 150 (see FIGS. 4, 5, and 6). The two surfaces can be formed on an integral stem as shown in FIG. 4 through FIG. 6, or can be formed by the use of a plurality of parts, as shown in FIG. 7. In operation, the valve surfaces 146 and 148 are positioned to engage the upper and lower edges of an opening 152 in a washer 154 to provide the valving action. In order to limit downward movement of said cup-like member 142, an outer cylindrical flange 143 (see FIG. 3) extends outwardly there from for engagement with a recess 145 in the flange 106.

When the pressure actuated valve 54 is mounted on the main flow valve 52, the washer 154 is positioned against the shoulder 65 and the external threads 108 on the short cylindrical section of lower housing body 102 threadably engage the threaded recess 59. The end of the lower housing body 102 engages the outer side face of the washer 154 fixedly mounting it in position and sealing it with cover 62. A spring 155 is positioned between the inside of cup-like member 142 and the washer 154 adjacent the lower housing body 102. In this mounted position, the free end of the valve stem 144 is positioned with the surface 146 above washer 154, connecting pin 150 through opening 152, and surface 148 below washer 154 in cylindrical section 61. The travel distance between recess 131 and 145 is made greater than the seating distance between valve faces 146 and 148 so that they will be movable between a lower closed position and an upper closed position. While the cup 130, diaphragm 126 and cup 142 need not be fixed together in view of the action of springs 134 and 155, they can be made as a unit if desired and fixed together by any means desired.

In assembling the valve stem 144 and washer 154 if an integral stem is used, as shown in FIGS. 4 through 6, it is necessary that a resilient material be used for the washer since the assembly is made by pushing the free end of the valve stem 144 through the opening 152 until the connecting pin 150 is in the opening. Ifa valve stem 144 is used as formed in FIG. 7, the washer 154 can be placed against the valve surface 146 and the member on which surface 148 is formed can then be fixed with respect to the main part of the stem.

Main flow valve 52 is opened when the opening or port 152 of pressure actuated valve 54 is open because this port 152 is designed to have approximately four times a larger flow area than the restriction 98 which is feeding pressure from the main valve inlet 74 to the cavity above the valve diaphragm 63. Thus at any time port 152 is opened, fluid pressure is dumped from above the main valve diaphragm 63 faster than it can be pressurized through restriction 98. Inlet line pressures then force diaphragm 63 up, against spring 89, opening the main valve.

The valve member of the pressure actuated valve 54 of a given main flow control valve unit 50 is assembled with the springs 134 and keeping valve seat 148 closed when the pressure delivered by tube 14 above diaphragm 126 is below the opening pressure (see FIG. 4), placing valve seat 148 in an open position while keeping valve seat 146 in an open" position when the pressure above diaphragm 126 is at the selected open pressure signal (see FIG. 5), and placing valve seat 146 in a closed position when the pressure above diaphragm 126 is above the open pressure signal (see FIG. 6). To accomplish this, it is necessary that spring 155 be sized to exert a bias against diaphragm 126 that will require the maximum open" signal pressure and an adjusted minimum force of spring 134 to keep both valve seats 146 and 148 open. Then for each other pressure actuated valve 54 of a given main flow control valve unit the spring 134 is sized or adjusted, using the threaded adjustment screw 132, to exert a bias against the diaphragm 126 to permit the desired pressure signal to press the valve seat 148 open and place the valve 54 in an open position when the desired open pressure signal is reached. The valve seat 146 is pressed down to place the valve 54 in a closed position for signal pressures higher than the adjusted open level.

In the modification of the main flow control valve unit 50, shown in FIG. 8, the pressure actuated valve 54 as shown in FIG. 3, is moved to the left side of the main flow valve 52. The manually actuated valve 56 is moved to another location not shown. This pressure actuated valve is numbered 54A. The construction of the pressure actuated valve 54A is identical to that of valve 54 of FIG. 3 with the addition of a valve member 200 on a rod extending from the bottom of the valve stem 144.'The valve member 200 is sized to cooperate with the restricted opening 202. As the pressure actuated valve 54A moves between its operating positions, the valve member 200 cooperates with the restricted opening 202 in the following manner:

I. When the valve seat 148A is closed against the opening 152A in the washer 154A at a low pressure signal. the valve member 200 is located above the restricted opening 202 to permit flow to pass from the inlet 74 to the area above the diaphragm 63 through connecting passage 96 to pressurize it, and close the main flow valve 52.

2. When the valve seat 148A is moved to an open position by a pressure signal, the valve seat 146A remains open, and the valve member 200 is located in the restricted opening 202, inhibiting flow from passing from the inlet 74 to the area above the diaphragm 63 of the main valve. The volume above the main valve diaphragm is at this time vented to atmospheric pressure through passage 96, open pressure actuated valve 54, opening 152A, and tube 110. This opens main flow valve 52. The closing of the restricted opening 202 limits flow from the main line through the dump line.

3. When the valve seat 146A is closed against the opening 152A in the washer 154A at a higher pressure signal, the valve member 200 is located below the restricted opening 202 to permit flow to pass from the inlet 74 to the area above the diaphragm 63 to pressurize it and close the main flow valve 52.

in the modification of the main control valve unit 50, shown in FIG. 9, the pressure actuated valve 54 is changed in the following manner and is numbered 548. The construction of the pressure actuated valve 548 is identical to that of valve 54 of FIG. 3, except that the stem 144 has a seal member 220 held thereagainst by an inwardly extending flange member 222 extending from the inner side of lower housing body 102. The spring 155 abuts the flange member 222. The washer 1548 is formed as a cup with an annular groove 224 around its outer surface which is located therein to insure meeting with passage 67 to provide connection therebetween. Holes 226 connect the annular groove 224 to the interior of the cup. The cylindrical section 61B is connected to the passageway 79 by an opening 228 in diaphragm 63 and opening 230 in the outlet 76. When the pressure actuated valve 548 moves to its open position, the area above the diaphragm 63 is connected to the lower pressure passageway 79 causing the main valve 52 to open. By venting the fluid from above the main valve diaphragm back into the main valve discharge line overboard flow is eliminated out of conduit section 110 except for possibly some seal member 220 leakage. Conduit 110 provides only an ambient reference for one side of diaphragm 126 of pressure actuated valve 54.

I claim:

1. In combination, a fluid supply means, at least two fluid distribution units, conduit means extending from said fluid supply means to each distribution unit, separate valve means in each conduit means for controlling flow to each distribution unit, each valve means having a pressure actuated control means, signal fluid pressure means, a single signal tube for carrying a signal fluid pressure to both pressure actuated control means, said signal tube being connected between said signal fluid pressure means and both of said pressure actuated control means.

2. A combination as set forth in claim 1 wherein each pressure actuated control means is actuated by a different pressure level, and said signal fluid pressure means has means for varying the pressure level in said single signal tube including said two different pressure levels.

3. A combination as set forth in claim 1 wherein said fluid distribution units are sprinkler units.

4. A combination as set forth in claim 1 wherein said fluid supply means comprises a first fluid supply and a second fluid supply. said conduit means comprising a first conduit connecting said first fluid supply to one fluid distribution unit and a second conduit connecting said second fluid supply to another fluid distribution unit. a valve means being in each first and second conduit.

5. A combination as set forth in claim 1 wherein second valve means are located along said signal tube, a signal tube pressure control means being connected to said second valve means for controlling the pressure in said single signal tube at a plurality of different pressure levels for use in actuating each pressure actuated valve means.

6. A combination as set forth in claim 1 wherein the pressure actuated control means of each valve means includes a pressure responsive means responsive to a predetermined pressure signal for placing said valve means in an open or closed position, said pressure responsive means being biased in a direction to close said valve means by first spring means when the pressure in the signal tube is below that pressure signal necessary for opening said valve means, said pressure responsive means being biased in a direction to open said valve means by a second spring means and a predetermined pressure signal in the signal tube for opening said valve means, and said valve means being biased in a direction to close said valve means against the first spring means by the second spring means and the pressure in the signal tube when it is greater than that required for opening the valve means.

7. A combination as set forth in claim 2 wherein said means for varying the pressure level in said single signal tube includes a first valve means for increasing the pressure in said signal tube and a second valve means for decreasing the pressure in said signal tube, means for sensing the pressure in the signal tube, means for comparing the pressure in the signal tube with a desired pressure and changing the pressure in the signal tube to obtain the desired pressure if it does not exist in the signal tube.

8. A flow control unit having an inlet and outlet, valve means for controlling flow through said unit from said inlet to said outlet, said valve means having a pressure actuated control means, said control means including a pressure responsive means responsive to a predetermined pressure signal for placing said valve means in an open or closed position, said pressure responsive means being biased in a direction to close said valve means by first spring means when the pressure on the other side of the pressure responsive means is below that pressure signal necessary for opening said valve means, said pressure responsive means being biased in a direction to open said valve means by a second spring means and a predetermined pressure signal on the other side of the pressure responsive means for opening said valve means, and said pressure responsive means being biased in a direction to close said valve means against the first spring means by the second spring means and the pressure on the other side of the pressure responsive means when it is greater than that required for opening the valve means.

9. A flow control unit as set forth in claim 8 wherein means are provided to change the tension of the second spring means to permit different predetermined pressure signals to operate said flow control unit.

10. A flow control unit as set forth in claim 8 wherein said pressure responsive means is a diaphragm.

11. A flow control unit having an inlet and outlet, first valve means for controlling flow through said unit from said inlet to said outlet, said first valve means having a first pressure responsive means responsive to inlet pressure for closing said valve means, second valve means for dumping inlet pressure from behind said first responsive means to open said first valve means, said second valve means having a second pressure responsive means responsive to a predetermined pressure signal for placing said second valve means in an open or closed position, said second pressure responsive means being biased in a direction to close said second valve means by first spring means when the pressure on the other side of the second pressure responsive means is below that pressure signal necessary for opening said second valve means, said second pressure responsive means being biased in a direction to open said second valve means by a second spring means and a predetermined pressure signal on the other side of the second pressure responsive means for opening said second valve means, and said second pressure responsive means being biased in a direction to close said second valve means against the first spring means by the second spring means and the pressure on the other side of the second pressure responsive means when it is greater than that required for opening the second valve means.

12. A flow control unit as set forth in claim 11 wherein said second pressure responsive means is a diaphragm, a first chamber being located above said diaphragm, a second chamber being located below said diaphragm, means for directing a pressure responsive signal to said first chamber, said second chamber being connected to the atmosphere for dumping, said second valve means being located for dumping inlet pressure from behind said first pressure responsive means into said second chamber.

13. Means for directing a flow of fluid to two distribution units including, means providing a main fluid source, means providing a signal fluid pressure source, means for directing a flow of fluid from said main fluid source to one of said distribution units by a predetermined pressure signal level from said signal fluid pressure source and for directing a flow of fluid from said main fluid source to the other distribution unit by a second and different predetermined pressure signal level from said signal fluid pressure source.

14. A method of distributing fluid over an area, including a. dividing said area into sections,

b. providing a main fluid source,

c. providing a signal fluid pressure source,

d. directing a flow of fluid from said main fluid source to different sections by a different predetermined pressure signal level from said signal fluid pressure source.

15. A flow control unit having an inlet and outlet, valve means for controlling flow through said unit from said inlet to said outlet, said valve means having a pressure actuated control means, said control means including a pressure responsive means responsive to a predetermined pressure signal for placing said valve means in an open or closed position, said pressure responsive means being biased in a direction to close said valve means by a force including first spring means when the pressure on the other side of the pressure responsive means is below that pressure signal necessary for opening said valve means, said pressure responsive means being biased in a direction to open said valve means by a force including a predetermined pressure signal on the other side of the pressure responsive means for opening said valve means, and said pressure responsive means being biased in a direction to close said valve means against the first spring means by a force including the pressure on the other side of the pressure responsive means when it is greater than that required for opening the valve means.

16. A flow control unit as set forth in claim 11 wherein passage means are provided for directing inlet pressure behind said first responsive means, third valve means in said passage means for controlling the flow therein, said third valve means being connected to said first valve means, said third valve means being placed in a closed position when said second valve means is placed in an open position and said third valve means being placed in an open position when said second valve means is placed in a closed position.

17. A flow control unit as set forth in claim 11 wherein passage means are provided for directing inlet pressure behind said first responsive means to said outlet, said second valve means being located in said passage means.

18. A combination as set forth in claim 13 wherein a single signal tube connects said signal fluid pressure source to said means for directing a flow of fluid from said main fluid source, said means providing a signal fluid pressure source including means for placing different predetermined pressure signal levels in said single signal tube.

19. A combination as set forth in claim 18 wherein one valve means controls the flow of main fluid to one of said distribution units and another valve means controls said flow of main fluid to the other distribution unit, said single signal tube being connected to both of said valve means for providing a signal fluid pressure to both of said valve means, one of said valve means being operable by one predetermined pressure signal level while the other valve means is operable by another predetermined pressure signal level, said means providing a signal fluid pressure source having means for placing said different pressure signal levels in the single signal tube. 

1. In combination, a fluid supply means, at least two fluid distribution units, conduit means extending from said fluid supply means to each distribution unit, separate valve means in each conduit means for controlling flow to each distribution unit, each valve means having a pressure actuated control means, signal fluid pressure means, a single signal tube for carrying a signal fluid pressure to both pressure actuated control means, said signal tube being connected between said signal fluid pressure means and both of said pressure actuated control means.
 2. A combination as set forth in claim 1 wherein each pressure actuated control means is actuated by a different pressure level, and said signal fluid pressure means has means for varying the pressure level in said single signal tube including said two different pressure levels.
 3. A combination as set forth in claim 1 wherein said fluid distribution units are sprinkler units.
 4. A combination as set forth in claim 1 wherein said fluid supply means comprises a first fluid supply and a second fluid supply, said conduit means comprising a first conduit connecting said first fluid supply to one fluid distribution unit and a second conduit connecting said second fluid supply to another fluid distribution unit, a valve means being in each first and second conduit.
 5. A combination as set forth in claim 1 wherein second valve means are located along said signal tube, a signal tube pressure control means being connected to said second valve means for controlling the pressure in said single signal tube at a plurality of different pressure levels for use in actuating each pressure actuated valve means.
 6. A combination as set forth in claim 1 wherein the pressure actuated control means of each valve means includes a pressure responsive means responsive to a predetermined pressure signal for placing said valve means in an open or closed position, said pressure responsive means being biased in a direction to close said valve means by first spring means when the pressure in the signal tube is below that pressure signal necessary for opening said valve means, said pressure responsive means being biased in a direction to open said valve means by a second spring means and a predetermined pressure signal in the signal tube for opening said valve means, and said valve means being biased in a direction to close said valve means against the first spring means by the second spring means and the pressure in the signal tube when it is greater than that required for opening the valve means.
 7. A combination as set forth in claim 2 wherein said means for varying the pressure level in said single signal tube includes a first valve means for increasing the pressure in said signal tube and a second valve means for decreasing the pressure in said signal tube, means for sensing the pressure in the signal tube, means for comparing the pressure in the signal tube with a desired pressure and changing the pressure in the signal tube to obtain the desired pressure if it does not exist in the signal tube.
 8. A flow control unit having an inlet and outlet, valve means for controlling flow through said unit from said inlet to said outlet, said valve means having a pressure actuated control means, said control means including a pressure responsive means responsive to a predetermined pressure signal for placing said valve means in an open or closed position, said pressure responsive means being biased in a direction to close said valve means by first spring means when the pressure on the other side of the pressure responsive means is below that pressure signal necessary for opening said valve means, said pressure responsive means being biased in a direction to open said valve means by a second spring means and a predetermined pressure signal on the other side of the pressure responsive means for opening said valve means, and said pressure responsive means being biased in a direction to close said valve means against the first spring means by the second spring means and the pressure on the other side of the pressure responsive means when it is greater than that required for opening the valve means.
 9. A flow control unit as set forth in claim 8 wherein means are provided to change the tension of the second spring means to permit different predetermined pressure signals to operate said flow control unit.
 10. A flow control uniT as set forth in claim 8 wherein said pressure responsive means is a diaphragm.
 11. A flow control unit having an inlet and outlet, first valve means for controlling flow through said unit from said inlet to said outlet, said first valve means having a first pressure responsive means responsive to inlet pressure for closing said valve means, second valve means for dumping inlet pressure from behind said first responsive means to open said first valve means, said second valve means having a second pressure responsive means responsive to a predetermined pressure signal for placing said second valve means in an open or closed position, said second pressure responsive means being biased in a direction to close said second valve means by first spring means when the pressure on the other side of the second pressure responsive means is below that pressure signal necessary for opening said second valve means, said second pressure responsive means being biased in a direction to open said second valve means by a second spring means and a predetermined pressure signal on the other side of the second pressure responsive means for opening said second valve means, and said second pressure responsive means being biased in a direction to close said second valve means against the first spring means by the second spring means and the pressure on the other side of the second pressure responsive means when it is greater than that required for opening the second valve means.
 12. A flow control unit as set forth in claim 11 wherein said second pressure responsive means is a diaphragm, a first chamber being located above said diaphragm, a second chamber being located below said diaphragm, means for directing a pressure responsive signal to said first chamber, said second chamber being connected to the atmosphere for dumping, said second valve means being located for dumping inlet pressure from behind said first pressure responsive means into said second chamber.
 13. Means for directing a flow of fluid to two distribution units including, means providing a main fluid source, means providing a signal fluid pressure source, means for directing a flow of fluid from said main fluid source to one of said distribution units by a predetermined pressure signal level from said signal fluid pressure source and for directing a flow of fluid from said main fluid source to the other distribution unit by a second and different predetermined pressure signal level from said signal fluid pressure source.
 14. A method of distributing fluid over an area, including a. dividing said area into sections, b. providing a main fluid source, c. providing a signal fluid pressure source, d. directing a flow of fluid from said main fluid source to different sections by a different predetermined pressure signal level from said signal fluid pressure source.
 15. A flow control unit having an inlet and outlet, valve means for controlling flow through said unit from said inlet to said outlet, said valve means having a pressure actuated control means, said control means including a pressure responsive means responsive to a predetermined pressure signal for placing said valve means in an open or closed position, said pressure responsive means being biased in a direction to close said valve means by a force including first spring means when the pressure on the other side of the pressure responsive means is below that pressure signal necessary for opening said valve means, said pressure responsive means being biased in a direction to open said valve means by a force including a predetermined pressure signal on the other side of the pressure responsive means for opening said valve means, and said pressure responsive means being biased in a direction to close said valve means against the first spring means by a force including the pressure on the other side of the pressure responsive means when it is greater than that required for opening the valve means.
 16. A flow control unit as set forth in claim 11 wheRein passage means are provided for directing inlet pressure behind said first responsive means, third valve means in said passage means for controlling the flow therein, said third valve means being connected to said first valve means, said third valve means being placed in a closed position when said second valve means is placed in an open position and said third valve means being placed in an open position when said second valve means is placed in a closed position.
 17. A flow control unit as set forth in claim 11 wherein passage means are provided for directing inlet pressure behind said first responsive means to said outlet, said second valve means being located in said passage means.
 18. A combination as set forth in claim 13 wherein a single signal tube connects said signal fluid pressure source to said means for directing a flow of fluid from said main fluid source, said means providing a signal fluid pressure source including means for placing different predetermined pressure signal levels in said single signal tube.
 19. A combination as set forth in claim 18 wherein one valve means controls the flow of main fluid to one of said distribution units and another valve means controls said flow of main fluid to the other distribution unit, said single signal tube being connected to both of said valve means for providing a signal fluid pressure to both of said valve means, one of said valve means being operable by one predetermined pressure signal level while the other valve means is operable by another predetermined pressure signal level, said means providing a signal fluid pressure source having means for placing said different pressure signal levels in the single signal tube. 